'They gave me liberation," says Amy Rosenthal who is sitting outside the Hampstead Theatre on a blustery afternoon, sipping green tea.
It was here in 2008 that Rosenthal's DH Lawrence biopic On the Rocks became a rare success for the venue in the days before the theatre's current artistic director Edward Hall took over.
But Rosenthal is not talking about the Hampstead, or On the Rocks. Liberation is the name and subject of the playwright's latest offering.
Written for The Other Seder, the Jewish Community Centre's annual cultural celebration of Passover, the 15-minute play will appear at The Tricycle Theatre on April 10 along with three other short works, each written by a leading Jewish playwright.
The four writers were given free rein to interpret stages between slavery and freedom as represented by the four cups of wine during the Seder.
Rosenthal's Liberation is set during freshers' week at a university where a student finds it difficult to make the transition from home to university. Arnold Wesker's Deliverance features a couple who fantasise about how a windfall can change their life; Eve Ensler's Release takes the form of an interview between a journalist and a raped Congolese woman who attempts to take control of her life's story; and Ryan Craig's Redemption examines the effects on a suburban housewife after she slaps a teenage girl on her street corner. The four playlets are being directed by Mark Rosenblatt.
"I'm in good company", says Rosenthal of her fellow playwrights. Ensler is the writer who created the theatrical phenomenon The Vagina Monologues; Wesker is about to be back in the big time with a major Royal Court Revival of Chicken Soup With Barley; and Craig's The Holy Rosenbergs with Henry Goodman is currently at the National Theatre.
In creating her contribution, Rosenthal went through a familiar process of negotiating the writer's block that has plagued her career, and expunging the self-doubt that makes her reject good ideas for not being good enough.
After she thought of the university idea, the self-doubt was saying, "Liberation should be exciting. You should be thinking of something where there is a moment of absolute release."
But the problem was that Rosenthal has rarely associated liberation with excitement and release. Take her first play Sitting Pretty, the idea for which occurred to her just after she left school at 18. Though the play is about a middle-aged woman who has been made redundant, it was inspired by Rosenthal hating the idea of leaving school and moving on.
"My school life had reached its natural end," she remembers. "The doors were opened and while all the other girls in my year flooded out, I clung onto the banisters and didn't want to leave. And that's where the idea for Sitting Pretty came. It's about someone losing their job and not knowing where to go."
It is not too fanciful then to say that the theme of Rosenthal's latest play is connected to the subject of her first. Not that there is anything wrong with that. Playwrights have their themes, and one of Rosenthal's is how liberation can be thrilling for some but, to use her own phrase, "a completely terrifying concept" for others.
The playwright does not want to get too self-analytical about all this but from the point of view of a woman in her mid-30s, Rosenthal now suspects that there was something profound behind that school-leaver's terror, and which also explains why she wanted her father Jack - the television dramatist whose name is usually preceded by the words late and great - to stick around for a week after he drove her from the family house in Muswell Hill to Manchester University.
Yes, Liberation is very much an autobiographical play.
"He drove me up there and he stayed (in a hotel) for the first week," remembers Rosenthal. "We had a great time. And then he left and I didn't know anyone."
This is basically what happens to the fresher Evie in Rosenthal's play. On the page at least, Liberation is typical Rosenthal - that is, typical Amy Rosenthal, rather than typical Jack. Just when it seems unlikely that the play's breezy wit will touch the deeper emotions, you cry.
"There was some sense of mortality, or my dad's mortality behind it," says Rosenthal of that terror of transition. "I think I just felt that by going along with what is normal, I was agreeing to something that I didn't want. And that by rebelling against it, and stubbornly staying in childhood in some way, I was at least delaying some inevitable change - or inevitable death."
This was a long time before her father became ill with myeloma, the disease that killed him in 2004.
His work lives on though, now more than ever.
This week the BBC belatedly released a long-awaited box set of Jack Rosenthal television plays. It includes Bar Mitzvah Boy which Amy is now in the process of adapting for radio. And in a few days' time she and her actor mother Maureen Lipman will be at the Menier Chocolate Factory for the opening of Jack's stage play Smash (see review on page 44) which is based on the failed musical version of Bar Mitzvah Boy.
Amy has been working on the Smash script too, though only tinkering she says. It must be difficult to be a playwright so closely associated with the work of another dramatist - even, or especially, if he is your father.
"It is," says Rosenthal candidly. "I think with my own play Liberation I'm sort of complicit in that. Sometimes I feel that it should be my turn. But then I am very proud as well. It's a conflict."
On the plus side, working on her father's plays has served as a useful antidote to the writer's block that has sometimes ground a promising career to a halt. There is also another string to Rosenthal's bow - that of a portrait artist who paints her subjects on Russian dolls. Whole families have been captured this way. For one customer - a fanatical Madonna fan - Rosenthal painted the star in her various guises through her pop career.
"I do it partly to make sure the creative flame never gets extinguished," she says. And although commissions for the Russian doll portraits are coming in - each set takes about three weeks - painting will never take the place of writing.
"This may sound ridiculous from someone like me who so often struggles with writing plays", she says, giving her now chilled tea a stir, "but I am utterly driven and completely passionate about writing, and about being in theatres and working with actors and seeing work come to life on stage. I think I am a perfectionist. Possibly to my own detriment."
'The Other Seder' is at The Tricycle Theatre on April 10.